Research related to metal-organic frameworks (MOFs) as well as coordination polymers (CPs) (for a perspective understanding of the differences between the terms CP, MOF and hybrid organic-inorganic materials, see Biradha et al., 2009) has been treated with overwhelming interest by the scientific community of chemists and physicists due to tunable properties of these molecular assemblies by controlling their growth, size and shape, and their potential applications in the fields of catalysis, gas storage, separation, recognition and purification, optics, sensors, etc. (Zhao et al., 2004; Yaghi et al., 2003; Seo et al., 2000; Kitagawa et al., 2004; Evans and Lin, 2002; Rowsell and Yaghi, 2005; Tabellion et al., 2001; Lei et al., 2007; Zhao et al., 2008; Chen et al., 2010). It was in 1964 that J. C. Bailar defined the term “coordination polymer” (Bailar, 1964) and a wide variety of techniques such as solvothermal (Jung and Oh, 2008; Ni and Masel, 2006), precipitation (Oh and Mirkin, 2005; Oh and Mirkin, 2006; Sun et al., 2005; Park et al., 2006; Wei et al., 2007) and reverse microemulsion (Rieter et al., 2006) methods have been employed in the generation of shape selective nano and micro structured CPs (Wang et al., 2009; Shi et al., 2011; Liu et al., 2010; Lu et al., 2011; Li et al., 2011; Cho et al., 2008).
Structural uniformity is a prerequisite for many real-world applications that involve oriented fabrication of various materials, often in size-confined regimes (Tuxen et al., 2013). At the same time, structural diversity can lead to control of desired physical and chemical properties (Noorduin et al., 2013; Pevzner et al., 2012; Whitesides and Grzybowski, 2002; Masoomi and Morsali, 2013; Gu et al., 2012). Molecular self-assembly allows the construction of composite superstructures with unique structure and properties. Size and shape confined synthesis of such composites are advantageous for their intrinsic and complex multi-functionalities, allows addressing properties of individual components and the combination thereof, and the possibilities of their spatial integration into devices and onto surfaces (Carné-Sánchez et al., 2014). Needless to say “structure dictates function at all scales” (Tao et al., 2008).
Due to their unique, often porous structures and special properties achieved through synthetic tunability, MOFs have been actively studied over the last few decades (Furukawa et al., 2013; Cook et al., 2013; Long and Yaghi, 2009). However, control over their spatial topologies at the micro and nano levels is still limited and difficult to achieve (Stock and Biswas, 2011; Sindoro et al., 2014). Many variables, e.g., anions, solvents, and electronic configuration, play a key role in the formation of geometrically well-defined and uniform shapes. Thus far, the shapes of MOFs are limited to simple polyhedra (Sindoro et al., 2014).